Generation of reactive oxygen species by photolysis of the ruthenium(II) complex Ru(NH3)5(pyrazine)~(2+) in oxygenated solution

摘要

Metal-to-ligand charge transfer photolysis of the ruthe-nium(II) pyrazine complex Ru(NH3)5pz~(2+) (I) in pH 7.4 oxygenated phosphate buffer solution generates the Ru(ra) analog Ru(NH3)5pz~(3+) plus the reactive oxygen species singlet oxygen and superoxide.Based on the very short MLCT lifetime (re-measured as ~250 ps in D2O) of I* and the quantum yield for singlet oxygen formation (0.01 for aerated D2O) the rate constant for oxygen quenching of I* was calculated to be ~(3 +- 1) x 10~(10) M~(-1) s~(-1).